Photovoltaic energy is becoming a very significant source of electrical power. The roofs of building structures are directly exposed to solar radiation, and are particularly well suited for supporting photovoltaic generating devices. In this regard, the prior art has developed various roofing structures and members which are capable of generating photovoltaic power. Many of such prior art structures are cumbersome, expensive, and very difficult to install. Therefore, the prior art has sought methods and devices whereby a photovoltaic generating material may be disposed upon a roofing structure by simple techniques which are preferably compatible with conventional building practices, and in that regard it is desirable to have photovoltaic roofing material which is as much like conventional roofing material as possible. The photovoltaic portion of the roofing material should be self contained to a large degree and the roofing material should be capable of being installed by conventional techniques.
U.S. Pat. Nos. 5,437,735 and 5,575,861 both disclose photovoltaic shingle structures which are lightweight, flexible, and compatible with standard building structures, materials and practices. The disclosure of these two patents is incorporated herein by reference, and all materials, methods and terms used herein shall be defined and interpreted in accord with the disclosure of those two patents, to the extent that such terms are not inconsistent therewith. While the materials and methods of the foregoing patents have been successfully utilized in a large number of building structures, use of those materials generally requires electrical leads to pass through a roof deck, or to pass under the shingle structures. Such “backside” connections can be difficult to implement, particularly when the shingles are installed onto buildings which do not have full attics or other access to the underside of the roof. In some instances, the through hole connections in the roof are perceived as compromising the integrity of the roof. Also, the backside connection nature of such devices makes them difficult to service or replace.
There is thus a need in the art for photovoltaic roofing members such as shingles which provide for front surface connections and which do not require penetration of a roof deck. Furthermore, such roofing materials should be capable of being installed by roofers without the need for specialized tools or training. As will be described herein, the present invention provides a photovoltaic, electrical generating, roofing structure which meets these requirements.